@article{22089, abstract = {We consider the focusing energy-critical nonlinear Schr\"odinger equation $iu_t+\Delta u = - |u|^{4\over{d-2}}u$ in dimensions $d\geq 5$. We prove that if a maximal-lifespan solution $u\colon \ I\times {\Bbb R}^d\to {\Bbb C}$ obeys $\sup_{t\in I}\|\nabla u(t)\|_2<\|\nabla W\|_2$, then it is global and scatters both forward and backward in time. Here $W$ denotes the ground state, which is a stationary solution of the equation. In particular, if a solution has both energy and kinetic energy less than those of the ground state $W$ at some point in time, then the solution is global and scatters. We also show that any solution that blows up with bounded kinetic energy must concentrate at least the kinetic energy of the ground state. Similar results were obtained by Kenig and Merle for spherically symmetric initial data and dimensions $d=3,4,5$. }, author = {Killip, Rowan and Visan, Monica}, issn = {1080-6377}, journal = {American Journal of Mathematics}, number = {2}, pages = {361--424}, publisher = {Johns Hopkins University Press}, title = {{The focusing energy-critical nonlinear Schrödinger equation in dimensions five and higher}}, doi = {10.1353/ajm.0.0107}, volume = {132}, year = {2010}, } @article{3867, abstract = {Weighted automata are nondeterministic automata with numerical weights on transitions. They can define quantitative languages L that assign to each word w a real number L(w). In the case of infinite words, the value of a run is naturally computed as the maximum, limsup, liminf, limit-average, or discounted-sum of the transition weights. The value of a word w is the supremum of the values of the runs over w. We study expressiveness and closure questions about these quantitative languages. We first show that the set of words with value greater than a threshold can be omega-regular for deterministic limit-average and discounted-sum automata, while this set is always omega-regular when the threshold is isolated (i.e., some neighborhood around the threshold contains no word). In the latter case, we prove that the omega-regular language is robust against small perturbations of the transition weights. We next consider automata with transition weights 0 or 1 and show that they are as expressive as general weighted automata in the limit-average case, but not in the discounted-sum case. Third, for quantitative languages L-1 and L-2, we consider the operations max(L-1, L-2), min(L-1, L-2), and 1 - L-1, which generalize the boolean operations on languages, as well as the sum L-1 + L-2. We establish the closure properties of all classes of quantitative languages with respect to these four operations.}, author = {Chatterjee, Krishnendu and Doyen, Laurent and Henzinger, Thomas A}, journal = {Logical Methods in Computer Science}, number = {3}, pages = {1 -- 23}, publisher = {International Federation for Computational Logic}, title = {{Expressiveness and closure properties for quantitative languages}}, doi = {10.2168/LMCS-6(3:10)2010}, volume = {6}, year = {2010}, } @article{3868, abstract = {Simulation and bisimulation metrics for stochastic systems provide a quantitative generalization of the classical simulation and bisimulation relations. These metrics capture the similarity of states with respect to quantitative specifications written in the quantitative mu-calculus and related probabilistic logics. We first show that the metrics provide a bound for the difference in long-run average and discounted average behavior across states, indicating that the metrics can be used both in system verification, and in performance evaluation. For turn-based games and MDPs, we provide a polynomial-time algorithm for the computation of the one-step metric distance between states. The algorithm is based on linear programming; it improves on the previous known exponential-time algorithm based on a reduction to the theory of reals. We then present PSPACE algorithms for both the decision problem and the problem of approximating the metric distance between two states, matching the best known algorithms for Markov chains. For the bisimulation kernel of the metric our algorithm works in time O(n(4)) for both turn-based games and MDPs; improving the previously best known O(n(9).log(n)) time algorithm for MDPs. For a concurrent game G, we show that computing the exact distance be tween states is at least as hard as computing the value of concurrent reachability games and the square-root-sum problem in computational geometry. We show that checking whether the metric distance is bounded by a rational r, can be done via a reduction to the theory of real closed fields, involving a formula with three quantifier alternations, yielding O(vertical bar G vertical bar(O(vertical bar G vertical bar 5))) time complexity, improving the previously known reduction, which yielded O(vertical bar G vertical bar(O(vertical bar G vertical bar 7))) time complexity. These algorithms can be iterated to approximate the metrics using binary search}, author = {Chatterjee, Krishnendu and De Alfaro, Luca and Majumdar, Ritankar and Raman, Vishwanath}, journal = {Logical Methods in Computer Science}, number = {3}, pages = {1 -- 27}, publisher = {International Federation for Computational Logic}, title = {{Algorithms for game metrics}}, doi = {10.2168/LMCS-6(3:13)2010}, volume = {6}, year = {2010}, } @inproceedings{3782, abstract = {In cortex surface segmentation, the extracted surface is required to have a particular topology, namely, a two-sphere. We present a new method for removing topology noise of a curve or surface within the level set framework, and thus produce a cortical surface with correct topology. We define a new energy term which quantifies topology noise. We then show how to minimize this term by computing its functional derivative with respect to the level set function. This method differs from existing methods in that it is inherently continuous and not digital; and in the way that our energy directly relates to the topology of the underlying curve or surface, versus existing knot-based measures which are related in a more indirect fashion. The proposed flow is validated empirically.}, author = {Chen, Chao and Freedman, Daniel}, booktitle = {Conference proceedings MCV 2010}, location = {Beijing, China}, pages = {31 -- 42}, publisher = {Springer}, title = {{Topology noise removal for curve and surface evolution}}, doi = {10.1007/978-3-642-18421-5_4}, volume = {6533}, year = {2010}, } @article{3789, abstract = {The development of multicellular organisms is dependent on the tight coordination between tissue growth and morphogenesis. The stereotypical orientation of cell divisions has been proposed to be a fundamental mechanism by which proliferating and growing tissues take shape. However, the actual contribution of stereotypical division orientation (SDO) to tissue morphogenesis is unclear. In zebrafish, cell divisions with stereotypical orientation have been implicated in both body-axis elongation and neural rod formation [1, 2], although there is little direct evidence for a critical function of SDO in either of these processes. Here we show that SDO is required for formation of the neural rod midline during neurulation but dispensable for elongation of the body axis during gastrulation. Our data indicate that SDO during both gastrulation and neurulation is dependent on the noncanonical Wnt receptor Frizzled 7 (Fz7) and that interfering with cell division orientation leads to severe defects in neural rod midline formation but not body-axis elongation. These findings suggest a novel function for Fz7-controlled cell division orientation in neural rod midline formation during neurulation. }, author = {Quesada-Hernández, Elena and Caneparo, Luca and Schneider, Sylvia and Winkler, Sylke and Liebling, Michael and Fraser, Scott and Heisenberg, Carl-Philipp J}, journal = {Current Biology}, number = {21}, pages = {1966 -- 1972}, publisher = {Cell Press}, title = {{Stereotypical cell division orientation controls neural rod midline formation in zebrafish}}, doi = {10.1016/j.cub.2010.10.009}, volume = {20}, year = {2010}, } @article{22446, abstract = {By partitioning mass and energy fluxes, soil moisture exerts a fundamental control on basin hydrological response. Using the design characteristics of the Biosphere 2 hillslope experiment, this study investigates aspects of soil moisture spatial and temporal variability in a zero‐order catchment of a semiarid climate. The hydrological response of the domain exhibits a particular structure, which depends on whether topography‐induced subsurface stormflow is triggered. The occurrence of the latter is conditioned by topography, soil depth, and pre‐storm spatial distribution of moisture. As a result, a non‐unique behavior of soil moisture spatial heterogeneity emerges, manifested through a hysteretic dependence of variability metrics on mean water content. Further, it is argued that vegetation dynamics impose a “homogenizing” effect on pre‐storm moisture states, decreasing the likelihood that a rainfall event will result in topographic redistribution of soil water. Consequently, post‐rainfall soil moisture dynamics associated with the effect of topography that could lead to the enhancement of spatial heterogeneity are suppressed; a potential “attractor” of catchment states emerges. The study thus proposes several hypotheses that will be testable within the framework of long‐term hillslope experiments.}, author = {Ivanov, Valeriy Y. and Fatichi, Simone and Jenerette, G. Darrel and Espeleta, Javier F. and Troch, Peter A. and Huxman, Travis E.}, issn = {1944-7973}, journal = {Water Resources Research}, number = {9}, publisher = {American Geophysical Union}, title = {{Hysteresis of soil moisture spatial heterogeneity and the “homogenizing” effect of vegetation}}, doi = {10.1029/2009wr008611}, volume = {46}, year = {2010}, } @article{110, abstract = {In order to better understand magnetic reconnection and particle acceleration in solar flares, we compare the RHESSI hard X-ray (HXR) footpoint motions of three flares with a detailed study of the corresponding topology given by a Magnetic Charge Topology model. We analyze the relationship between the footpoint motions and topological spine lines and find that the examined footpoint sources move along spine lines. We present a three-dimensional topological model in which this movement can be understood. As reconnection proceeds, flux is transferred between the reconnecting domains, causing the separator to move. The movement of the separator\'s chromospheric ends, identified with the HXR footpoints, is along those spine lines on which the separator ends.}, author = {Des Jardins, Angela and Canfield, Richard and Longcope, Dana and Fordyce, Crystal and Waitukaitis, Scott R}, journal = {The Astrophysical Journal}, number = {2}, pages = {1628 -- 1636}, publisher = {IOP Publishing Ltd.}, title = {{Reconnection in three dimensions: The role of spines in three eruptive flares}}, doi = {10.1088/0004-637X/693/2/1628}, volume = {693}, year = {2009}, } @article{111, abstract = {Thin streams of liquid commonly break up into characteristic droplet patterns owing to the surface-tension-driven PlateauRayleigh instability 1-3. Very similar patterns are observed when initially uniform streams of dry granular material break up into clusters of grains4-6, even though flows of macroscopic particles are considered to lack surface tension7,8. Recent studies on freely falling granular streams tracked fluctuations in the stream profile9, but the clustering mechanism remained unresolved because the full evolution of the instability could not be observed. Here we demonstrate that the cluster formation is driven by minute, nanoNewton cohesive forces that arise from a combination of van der Waals interactions and capillary bridges between nanometre-scale surface asperities. Our experiments involve high-speed video imaging of the granular stream in the co-moving frame, control over the properties of the grain surfaces and the use of atomic force microscopy to measure grain-grain interactions. The cohesive forces that we measure correspond to an equivalent surface tension five orders of magnitude below that, of ordinary liquids. We find that, the shapes of these weakly cohesive, non-thermal clusters of macroscopic particles closely resemble droplets resulting from thermally induced rupture of liquid nanojets 10-12.}, author = {Royer, John and Evans, Daniel and Oyarte, Loreto and Guo, Qiti and Kapit, Eliot and Möbius, Matthias and Waitukaitis, Scott R and Jaeger, Heinrich}, journal = {Nature}, number = {7250}, pages = {1110 -- 1113}, publisher = {Nature Publishing Group}, title = {{High-speed tracking of rupture and clustering in freely falling granular streams}}, doi = {10.1038/nature08115}, volume = {459}, year = {2009}, } @article{11103, abstract = {Over the last decade, the nuclear envelope (NE) has emerged as a key component in the organization and function of the nuclear genome. As many as 100 different proteins are thought to specifically localize to this double membrane that separates the cytoplasm and the nucleoplasm of eukaryotic cells. Selective portals through the NE are formed at sites where the inner and outer nuclear membranes are fused, and the coincident assembly of ∼30 proteins into nuclear pore complexes occurs. These nuclear pore complexes are essential for the control of nucleocytoplasmic exchange. Many of the NE and nuclear pore proteins are thought to play crucial roles in gene regulation and thus are increasingly linked to human diseases.}, author = {HETZER, Martin W and Wente, Susan R.}, issn = {1534-5807}, journal = {Developmental Cell}, keywords = {Developmental Biology, Cell Biology, General Biochemistry, Genetics and Molecular Biology, Molecular Biology}, number = {5}, pages = {606--616}, publisher = {Elsevier}, title = {{Border control at the nucleus: Biogenesis and organization of the nuclear membrane and pore complexes}}, doi = {10.1016/j.devcel.2009.10.007}, volume = {17}, year = {2009}, } @article{11105, abstract = {Nuclear-pore complexes (NPCs) are large protein channels that span the nuclear envelope (NE), which is a double membrane that encloses the nuclear genome of eukaryotes. Each of the typically 2,000–4,000 pores in the NE of vertebrate cells is composed of multiple copies of 30 different proteins known as nucleoporins. The evolutionarily conserved NPC proteins have the well-characterized function of mediating the transport of molecules between the nucleoplasm and the cytoplasm. Mutations in nucleoporins are often linked to specific developmental defects and disease, and the resulting phenotypes are usually interpreted as the consequences of perturbed nuclear transport activity. However, recent evidence suggests that NPCs have additional functions in chromatin organization and gene regulation, some of which might be independent of nuclear transport. Here, we review the transport-dependent and transport-independent roles of NPCs in the regulation of nuclear function and gene expression.}, author = {Capelson, Maya and HETZER, Martin W}, issn = {1469-3178}, journal = {EMBO reports}, keywords = {Genetics, Molecular Biology, Biochemistry}, number = {7}, pages = {697--705}, publisher = {EMBO}, title = {{The role of nuclear pores in gene regulation, development and disease}}, doi = {10.1038/embor.2009.147}, volume = {10}, year = {2009}, } @article{11106, abstract = {Formation of the nuclear envelope (NE) around segregated chromosomes occurs by the reshaping of the endoplasmic reticulum (ER), a reservoir for disassembled nuclear membrane components during mitosis. In this study, we show that inner nuclear membrane proteins such as lamin B receptor (LBR), MAN1, Lap2β, and the trans-membrane nucleoporins Ndc1 and POM121 drive the spreading of ER membranes into the emerging NE via their capacity to bind chromatin in a collaborative manner. Despite their redundant functions, decreasing the levels of any of these trans-membrane proteins by RNAi-mediated knockdown delayed NE formation, whereas increasing the levels of any of them had the opposite effect. Furthermore, acceleration of NE formation interferes with chromosome separation during mitosis, indicating that the time frame over which chromatin becomes membrane enclosed is physiologically relevant and regulated. These data suggest that functionally distinct classes of chromatin-interacting membrane proteins, which are present at nonsaturating levels, collaborate to rapidly reestablish the nuclear compartment at the end of mitosis.}, author = {Anderson, Daniel J. and Vargas, Jesse D. and Hsiao, Joshua P. and HETZER, Martin W}, issn = {1540-8140}, journal = {Journal of Cell Biology}, keywords = {Cell Biology}, number = {2}, pages = {183--191}, publisher = {Rockefeller University Press}, title = {{Recruitment of functionally distinct membrane proteins to chromatin mediates nuclear envelope formation in vivo}}, doi = {10.1083/jcb.200901106}, volume = {186}, year = {2009}, } @article{11107, abstract = {Nucleocytoplasmic transport occurs exclusively through nuclear pore complexes (NPCs) embedded in pores formed by inner and outer nuclear membrane fusion. The mechanism for de novo pore and NPC biogenesis remains unclear. Reticulons (RTNs) and Yop1/DP1 are conserved membrane protein families required to form and maintain the tubular endoplasmic reticulum (ER) and the postmitotic nuclear envelope. In this study, we report that members of the RTN and Yop1/DP1 families are required for nuclear pore formation. Analysis of Saccharomyces cerevisiae prp20-G282S and nup133Δ NPC assembly mutants revealed perturbations in Rtn1–green fluorescent protein (GFP) and Yop1-GFP ER distribution and colocalization to NPC clusters. Combined deletion of RTN1 and YOP1 resulted in NPC clustering, nuclear import defects, and synthetic lethality with the additional absence of Pom34, Pom152, and Nup84 subcomplex members. We tested for a direct role in NPC biogenesis using Xenopus laevis in vitro assays and found that anti-Rtn4a antibodies specifically inhibited de novo nuclear pore formation. We hypothesize that these ER membrane–bending proteins mediate early NPC assembly steps.}, author = {Dawson, T. Renee and Lazarus, Michelle D. and HETZER, Martin W and Wente, Susan R.}, issn = {1540-8140}, journal = {Journal of Cell Biology}, keywords = {Cell Biology}, number = {5}, pages = {659--675}, publisher = {Rockefeller University Press}, title = {{ER membrane–bending proteins are necessary for de novo nuclear pore formation}}, doi = {10.1083/jcb.200806174}, volume = {184}, year = {2009}, } @article{11108, abstract = {In dividing cells, nuclear pore complexes (NPCs) disassemble during mitosis and reassemble into the newly forming nuclei. However, the fate of nuclear pores in postmitotic cells is unknown. Here, we show that NPCs, unlike other nuclear structures, do not turn over in differentiated cells. While a subset of NPC components, like Nup153 and Nup50, are continuously exchanged, scaffold nucleoporins, like the Nup107/160 complex, are extremely long-lived and remain incorporated in the nuclear membrane during the entire cellular life span. Besides the lack of nucleoporin expression and NPC turnover, we discovered an age-related deterioration of NPCs, leading to an increase in nuclear permeability and the leaking of cytoplasmic proteins into the nucleus. Our finding that nuclear “leakiness” is dramatically accelerated during aging and that a subset of nucleoporins is oxidatively damaged in old cells suggests that the accumulation of damage at the NPC might be a crucial aging event.}, author = {D'Angelo, Maximiliano A. and Raices, Marcela and Panowski, Siler H. and HETZER, Martin W}, issn = {0092-8674}, journal = {Cell}, keywords = {General Biochemistry, Genetics and Molecular Biology}, number = {2}, pages = {284--295}, publisher = {Elsevier}, title = {{Age-dependent deterioration of nuclear pore complexes causes a loss of nuclear integrity in postmitotic cells}}, doi = {10.1016/j.cell.2008.11.037}, volume = {136}, year = {2009}, } @inproceedings{11752, abstract = {We propose a model which suggests that structural martensitic transitions are related to significant changes in the electronic structure, and are effected by high-magnetic fields. The magnetic field dependence is considered unusual as many influential investigations of martensitic transitions have emphasized that the structural transitions are primarily lattice dynamical and are driven by the entropy due to the phonons. We provide a theoretical framework which can be used to describe the effect of high magnetic field on the transition and lattice dynamics in which the field dependence originates from the dielectric constant. The model is compared with some recent experimental results.}, author = {Yang, Xiaodong and Riseborough, Peter S and Modic, Kimberly A and Fisher, R A and Oppeil, C P and Finlayson, T R and Cooley, J C and Smith, J L and Goddard, P A and Silhanek, A V and Lashley, J C}, booktitle = {Journal of Physics: Conference Series}, issn = {1742-6596}, location = {Karlsruhe, Germany}, number = {3}, publisher = {IOP Publishing}, title = {{Influence of magnetic fields on structural martensitic transitions}}, doi = {10.1088/1742-6596/200/3/032062}, volume = {200}, year = {2009}, } @inproceedings{11799, abstract = {We study the problem of matching bidders to items where each bidder i has general, strictly monotonic utility functions u i,j (p j ) expressing her utility of being matched to item j at price p j . For this setting we prove that a bidder optimal outcome always exists, even when the utility functions are non-linear and non-continuous. Furthermore, we give an algorithm to find such a solution. Although the running time of this algorithm is exponential in the number of items, it is polynomial in the number of bidders.}, author = {Dütting, Paul and Henzinger, Monika H and Weber, Ingmar}, booktitle = {5th International Workshop on Internet and Network Economics}, isbn = {9783642108402}, issn = {1611-3349}, location = {Rome, Italy}, pages = {575--582}, publisher = {Springer Nature}, title = {{Bidder optimal assignments for general utilities}}, doi = {10.1007/978-3-642-10841-9_58}, volume = {5929}, year = {2009}, } @inproceedings{11905, abstract = {Given only the URL of a web page, can we identify its topic? This is the question that we examine in this paper. Usually, web pages are classified using their content, but a URL-only classifier is preferable, (i) when speed is crucial, (ii) to enable content filtering before an (objection-able) web page is downloaded, (iii) when a page's content is hidden in images, (iv) to annotate hyperlinks in a personalized web browser, without fetching the target page, and (v) when a focused crawler wants to infer the topic of a target page before devoting bandwidth to download it. We apply a machine learning approach to the topic identification task and evaluate its performance in extensive experiments on categorized web pages from the Open Directory Project (ODP). When training separate binary classifiers for each topic, we achieve typical F-measure values between 80 and 85, and a typical precision of around 85. We also ran experiments on a small data set of university web pages. For the task of classifying these pages into faculty, student, course and project pages, our methods improve over previous approaches by 13.8 points of F-measure.}, author = {Baykan, Eda and Henzinger, Monika H and Marian, Ludmila and Weber, Ingmar}, booktitle = {18th International World Wide Web Conference}, isbn = {978-1-60558-487-4}, location = {New York, NY, United States}, pages = {1109--1110}, publisher = {Association for Computing Machinery}, title = {{Purely URL-based topic classification}}, doi = {10.1145/1526709.1526880}, year = {2009}, } @inproceedings{11906, abstract = {In the origin detection problem an algorithm is given a set S of documents, ordered by creation time, and a query document D. It needs to output for every consecutive sequence of k alphanumeric terms in D the earliest document in $S$ in which the sequence appeared (if such a document exists). Algorithms for the origin detection problem can, for example, be used to detect the "origin" of text segments in D and thus to detect novel content in D. They can also find the document from which the author of D has copied the most (or show that D is mostly original.) We concentrate on solutions that use only a fixed amount of memory. We propose novel algorithms for this problem and evaluate them together with a large number of previously published algorithms. Our results show that (1) detecting the origin of text segments efficiently can be done with very high accuracy even when the space used is less than 1% of the size of the documents in $S$, (2) the precision degrades smoothly with the amount of available space, (3) various estimation techniques can be used to increase the performance of the algorithms.}, author = {Abdel Hamid, Ossama and Behzadi, Behshad and Christoph, Stefan and Henzinger, Monika H}, booktitle = {18th International World Wide Web Conference}, isbn = {978-160558487-4}, location = {Madrid, Spain}, pages = {61--70}, publisher = {Association for Computing Machinery}, title = {{Detecting the origin of text segments efficiently}}, doi = {10.1145/1526709.1526719}, year = {2009}, } @inproceedings{11912, abstract = {As the World Wide Web is growing rapidly, it is getting increasingly challenging to gather representative information about it. Instead of crawling the web exhaustively one has to resort to other techniques like sampling to determine the properties of the web. A uniform random sample of the web would be useful to determine the percentage of web pages in a specific language, on a topic or in a top level domain. Unfortunately, no approach has been shown to sample the web pages in an unbiased way. Three promising web sampling algorithms are based on random walks. They each have been evaluated individually, but making a comparison on different data sets is not possible. We directly compare these algorithms in this paper. We performed three random walks on the web under the same conditions and analyzed their outcomes in detail. We discuss the strengths and the weaknesses of each algorithm and propose improvements based on experimental results.}, author = {Baykan, Eda and Henzinger, Monika H and Keller, Stefan F. and de Castelberg, Sebastian and Kinzler, Markus}, booktitle = {26th International Symposium on Theoretical Aspects of Computer Science}, isbn = {978-3-939897-09-5}, issn = {1868-8969}, location = {Freiburg, Germany}, pages = {13--30}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{A comparison of techniques for sampling web pages}}, doi = {10.4230/LIPICS.STACS.2009.1809}, volume = {3}, year = {2009}, } @article{226, abstract = {The Manin conjecture is established for a split singular del Pezzo surface of degree four, with singularity type A4.}, author = {Timothy Browning and Derenthal, Ulrich}, journal = {Annales de l'Institut Fourier}, number = {3}, pages = {1231 -- 1265}, publisher = {Association des Annales de l'Institut Fourier}, title = {{Manin's conjecture for a quartic del Pezzo surface with A4 singularity}}, doi = {10.5802/aif.2462}, volume = {59}, year = {2009}, } @book{227, abstract = {Winner of the Ferran Sunyer i Balaguer Prize 2009. First attempt to systematically survey the range of available tools from analytic number theory that can be applied to study the density of rational points on projective varieties. Designed to rapidly guide the reader to the many areas of ongoing research in the domain. Provides an extensive bibliography.}, author = {Browning, Timothy D}, isbn = {9-783-0346-0128-3}, issn = {2296-505X}, pages = {XIII, 160}, publisher = {Birkhäuser Basel}, title = {{Quantitative Arithmetic of Projective Varieties}}, doi = {10.1007/978-3-0346-0129-0}, volume = {277}, year = {2009}, }